2009/5/25 Grobe, David Michael <dgr...@iupui.edu>: > Hey Matias: > > Thanks very much for your attention and comments. > > On the first issue, about loading the database, it turns out that GOLoad.java > DOES succeed; it loads all 8K nodes, and I can count them during a traversal > using GORead.java. (Just to be sure, I downloaded both programs directly > from the web site, recompiled, and executed. > > I was just wondering if the approach was reasonable, or whether it was ugly > and brutish. :-)
well, one giant main method always look brutish to me :) > > On the second issue, about searching the node space, I will look into the > Index package you mentioned.... > > A couple of other questions have come up: > > 1) Does the whole graph have to fit into memory to be usable? There is a > page about required memory, but it doesn't say what happens if the > recommended memory is not available. I was hoping that Neo4j would just use > some clever caching in RAM from disk, rather than fail completely when > manipulating very large databases. Don't worry. You can have neo4j scale to billions of primitives with just little RAM... http://wiki.neo4j.org/content/Guidelines_for_Building_a_Neo_App#Assume_the_node_space_is_always_in_memory_.28Neo_will_make_it_so.29 Just give the JVM a couple of hundreds of Mb and it'll surely run quite fine. There are also numerous tweaks with memory mapped files for the actual neo store files a.s.o. but that can come at a later time. f.ex. add the parameters: -Xmx512M -Xms512M to your java command > > 2) I am interested in storing RDF and there appears to be an RDF overlay for > Neo4j, but I couldn't find any user-type, tutorial documentation. Is there > any such documentation? There isn't any good documentation for just that at the moment. The RDF layer on top of neo consists of an RDF layer and optionally an additional small layer which makes it a Sesame/OpenRDF Sail http://www.openrdf.org/ Basically you whip up the whole thing like this: NeoService neo = new EmbeddedNeo( "my/path" ); IndexService indexService = new LuceneIndexService( neo ); RdfStore rdfStore = new VerboseQuadStore( neo, indexService ); Sail sail = new NeoSail( neo, rdfStore ); Here you've got a great Sail, ready to be used. Don't forget to shut down in the end... prefferable with a shutdown hook (java.lang.Runtime.getRuntime().addShutdownHook) in the order: sail, indexService, neo > > Thanks again for your attention, > > Michael Grobe > Indiana University > Just glad to help out Best, Mattias > > >> -----Original Message----- >> From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org] >> On Behalf Of Mattias Persson >> Sent: Monday, May 25, 2009 4:10 AM >> To: Neo user discussions >> Subject: Re: [Neo] basic Neo4j programs >> >> Hi David, >> >> I'm glad that you are taking interest in Neo4j! >> >> 2009/5/25 Grobe, David Michael <dgr...@iupui.edu>: >> > Hello: >> > >> > I was looking for a simple example that would read a data file and build >> a Neo4j graph. >> > >> > I didn't find that on the web site so I took your code snippets on >> > >> > http://dist.neo4j.org/basic-neo4j-code-examples-2008-05-08.pdf >> > >> > and wrote something on my own. >> > >> > as it happens it was more complicated than I had imagined, and my Java >> is not all that great, but I got some things to work and put them on a web >> page >> > >> > http://mypage.iu.edu/~dgrobe/neo4j/ >> > >> > (in slightly modified form) where I was hoping you could give them a >> quick look, relative to these questions: >> > >> > - I'm not sure if I used a "canonical" approach to building the graph, >> or created some mutant. In particular, along with the graph, I created a >> hash into the graph, because access only through the "reference" node did >> not seem adequate. >> >> Your code which loads the data into the database have this >> if-statement which connects only one specific node (wherever it may be >> in the input file) to the reference node. Isn't that why you don't >> find anything when traversing from the reference node? >> >> > > eo4j.org/mailman/listinfo/user > _______________________________________________ > Neo mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Mattias Persson, [matt...@neotechnology.com] Neo Technology, www.neotechnology.com _______________________________________________ Neo mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
